Pypi offers an xmlrpc service that can gives you once a day the download stats for your package. The problem is that for ploting a time serie you need the past datas. This package is made of two scripts :
Stats are fetched on pypi. It is based on http://www.codekoala.com/blog/2010/pypi-download-stats/
This scripts add to the original the usage and storing previous stats in ~/.pypi.stat.json
Install following Installation
get stats for a package (here we want download stats for numpy).
pypi_get_stat.py numpy
graph all known packages in the stored stats.
pypi_graph_stat.py
Contents: